hack: remove -installsuffix build flag
follow-up https://github.com/moby/moby/pull/44546#discussion_r1054961381

**- What I did**

`-installsuffix netgo` has been added in https://github.com/moby/moby/pull/10155 to work around a bug with "go build" but not required anymore since go 1.5: https://github.com/golang/go/commit/4dab6d01f12591f256d36b32cd6480ef679458f1

Also took the opportunity to:
* remove `ORIG_BUILDFLAGS` var that was used for the cross target but has been removed
in https://github.com/moby/moby/pull/44546 so not necessary anymore
* cleanup unnecessary vars in `make.sh` script
* display build cmd when `DOCKER_DEBUG` is set (had to remove extra tabs and new lines to avoid a clunky output)

**- How I did it**

**- How to verify it**

**- Description for the changelog**
<!--
Write a short (one line) summary that describes the changes in this
pull request for inclusion in the changelog:
-->


**- A picture of a cute animal (not mandatory but encouraged)**


hack/make/.go-autogen
#!/usr/bin/env bash

LDFLAGS="${LDFLAGS} \
	-X \"github.com/docker/docker/dockerversion.Version=${VERSION}\" \
	-X \"github.com/docker/docker/dockerversion.GitCommit=${GITCOMMIT}\" \
	-X \"github.com/docker/docker/dockerversion.BuildTime=${BUILDTIME}\" \
	-X \"github.com/docker/docker/dockerversion.PlatformName=${PLATFORM}\" \
	-X \"github.com/docker/docker/dockerversion.ProductName=${PRODUCT}\" \
	-X \"github.com/docker/docker/dockerversion.DefaultProductLicense=${DEFAULT_PRODUCT_LICENSE}\" \
"

# Compile the Windows resources into the sources
if [ "$(go env GOOS)" = "windows" ]; then
  if [ ! -x "$(command -v go-winres)" ]; then
    >&2 echo "go-winres not found, skipping manifesting binary"
  else
    (
      . hack/make/.mkwinres
      go generate -v "${GO_PACKAGE}"
    )
  fi
fi

#!/usr/bin/env bash

LDFLAGS="${LDFLAGS} \
-X \"github.com/docker/docker/dockerversion.Version=${VERSION}\" \
-X \"github.com/docker/docker/dockerversion.GitCommit=${GITCOMMIT}\" \
-X \"github.com/docker/docker/dockerversion.BuildTime=${BUILDTIME}\" \
-X \"github.com/docker/docker/dockerversion.PlatformName=${PLATFORM}\" \
-X \"github.com/docker/docker/dockerversion.ProductName=${PRODUCT}\" \
-X \"github.com/docker/docker/dockerversion.DefaultProductLicense=${DEFAULT_PRODUCT_LICENSE}\" "

# Compile the Windows resources into the sources
if [ "$(go env GOOS)" = "windows" ]; then
  if [ ! -x "$(command -v go-winres)" ]; then
    >&2 echo "go-winres not found, skipping manifesting binary"
  else
    (
      . hack/make/.mkwinres
      go generate -v "${GO_PACKAGE}"
    )
  fi
fi

Could be worth keeping the last quote on a separate line (it's easy to miss that it's there); probably that was one of the reasons to use the indentation here.