android-rebuild.sh: Don't run unit test suite if wine is not installed.

When cross-compiling Windows binaries with --mingw option, check that
'wine' is installed. If not, print a warning, otherwise run the unit
test suite as usual.

Also add a --no-tests command-line option to disable running the test
suite, for debugging purposes.

Change-Id: I8710be80a3eca72f507034334329785c20041668
diff --git a/android-configure.sh b/android-configure.sh
index bb09011..42fe51d 100755
--- a/android-configure.sh
+++ b/android-configure.sh
@@ -72,6 +72,9 @@
   ;;
   --no-pcbios) PCBIOS_PROBE=no
   ;;
+  --no-tests)
+  # Ignore this option, only used by android-rebuild.sh
+  ;;
   *)
     echo "unknown option '$opt', use --help"
     exit 1
@@ -103,6 +106,7 @@
     echo "  --gles-dir=PATH          specify path to GLES host emulation sources [auto-detected]"
     echo "  --no-gles                disable GLES emulation support"
     echo "  --no-pcbios              disable copying of PC Bios files"
+    echo "  --no-tests               don't run unit test suite"
     echo ""
     exit 1
 fi