This is on behalf of seanwxiang@tencent.com .

The commit “8210283: Support git as an SCM alternative in the build” used git as an SCM.
In the source package “https://github.com/openjdk/jdk8u/archive/refs/tags/jdk8u332-ga.tar.gz”，
the git information has been removed in the source package.

When we compile JDK with the source code from the package, we get the below error:
```
Building 'linux-x86_64-normal-server-release' (matching CONF=release)
/bin/sh: line 0: [: too many arguments
```

The root cause is the lack of a non-empty check in the function
```
define GetSourceTips
        $(CD) $(SRC_ROOT) ; \
        if [ -d $(SCM_DIR) -a "$(SCM_VERSION)" != "" ] ; then \
          $(ID_COMMAND) >> $@ ; \
        elif [ -f $(SCM_TIP_FILENAME) ] ; then \
          $(SCM_TIP_FILECMD) >> $@ ; \
        fi;
        $(PRINTF) "\n" >> $@
endef
```

In the scenario， SCM_DIR，SCM_VERSION，SCM_TIP_FILECMD aren’t defined. That causes the build failure.
we add a check with SCM to support the case where the SCM doesn‘t exist.