Use bazel syntax for fully qualified name in path property

A module reference to a fully qualified module in a path property looks
like:
  //path:module
And with a tag:
  //path:module{tag}

At the moment the checking is quite lax but some follow up changes will
make it much stricter.

Bug: 193228441
Test: m nothing
Change-Id: Ie42edcfa33ec66fda5d75b3df1da73f56f147afd

android/module_test.go

@@ -55,6 +55,27 @@ func TestSrcIsModule(t *testing.T) {
 			},
 			wantModule: "foo:bar",
 		},
+		{
+			name: "fully qualified",
+			args: args{
+				s: "//foo:bar",
+			},
+			wantModule: "//foo:bar",
+		},
+		{
+			name: "fully qualified with tag",
+			args: args{
+				s: "//foo:bar{.tag}",
+			},
+			wantModule: "//foo:bar{.tag}",
+		},
+		{
+			name: "invalid unqualified name",
+			args: args{
+				s: ":foo/bar",
+			},
+			wantModule: "",
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
@@ -128,6 +149,35 @@ func TestSrcIsModuleWithTag(t *testing.T) {
 			},
 			wantModule: "foo.bar}",
 		},
+		{
+			name: "fully qualified",
+			args: args{
+				s: "//foo:bar",
+			},
+			wantModule: "//foo:bar",
+		},
+		{
+			name: "fully qualified with tag",
+			args: args{
+				s: "//foo:bar{.tag}",
+			},
+			wantModule: "//foo:bar",
+			wantTag:    ".tag",
+		},
+		{
+			name: "invalid unqualified name",
+			args: args{
+				s: ":foo/bar",
+			},
+			wantModule: "",
+		},
+		{
+			name: "invalid unqualified name with tag",
+			args: args{
+				s: ":foo/bar{.tag}",
+			},
+			wantModule: "",
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {