Add supported variants to module-info

Export the list of variants (host, host_cross, device) a build module
supports to module-info for downstream tools. The values correspond to
the Soong `host_supported`, `host_cross_supported`, and `device_supported`
attribute values.

Bug: 220263783
Test: m out/target/product/vsoc_x86_64/module-info.json
Change-Id: I10ae6ea21791d0d100686dcabecbce543a9adc3f
diff --git a/core/tasks/module-info.mk b/core/tasks/module-info.mk
index e5ddb1a..8097535 100644
--- a/core/tasks/module-info.mk
+++ b/core/tasks/module-info.mk
@@ -27,6 +27,7 @@
 			'"data": [$(foreach w,$(sort $(ALL_MODULES.$(m).TEST_DATA)),"$(w)", )], ' \
 			'"runtime_dependencies": [$(foreach w,$(sort $(ALL_MODULES.$(m).LOCAL_RUNTIME_LIBRARIES)),"$(w)", )], ' \
 			'"data_dependencies": [$(foreach w,$(sort $(ALL_MODULES.$(m).TEST_DATA_BINS)),"$(w)", )], ' \
+			'"supported_variants": [$(foreach w,$(sort $(ALL_MODULES.$(m).SUPPORTED_VARIANTS)),"$(w)", )], ' \
 			'},\n' \
 	 ) | sed -e 's/, *\]/]/g' -e 's/, *\}/ }/g' -e '$$s/,$$//' >> $@
 	$(hide) echo '}' >> $@