v.vmod: cleanup vmod.mod_file_cacher API

vlib/v/builder/builder.v

@@ -197,7 +197,7 @@ fn module_path(mod string) string {
 
 pub fn (b Builder) find_module_path(mod, fpath string) ?string {
 	// support @VROOT/v.mod relative paths:
-	vmod_file_location := vmod.mod_file_cacher.get(fpath)
+	vmod_file_location := vmod.mod_file_cacher.get_by_file(fpath)
 	mod_path := module_path(mod)
 	mut module_lookup_paths := []string{}
 	if vmod_file_location.vmod_file.len != 0 && vmod_file_location.vmod_folder !in b.module_search_paths {

vlib/v/parser/comptime.v

@@ -22,7 +22,7 @@ fn (mut p Parser) hash() ast.HashStmt {
 		mut flag := val[5..]
 		// expand `@VROOT` to its absolute path
 		if flag.contains('@VROOT') {
-			vmod_file_location := vmod.mod_file_cacher.get(p.file_name_dir)
+			vmod_file_location := vmod.mod_file_cacher.get_by_folder(p.file_name_dir)
 			if vmod_file_location.vmod_file.len == 0 {
 				// There was no actual v.mod file found.
 				p.error('To use @VROOT, you need' + ' to have a "v.mod" file in ${p.file_name_dir},' +

vlib/v/scanner/scanner.v

@@ -796,7 +796,7 @@ pub fn (mut s Scanner) scan() token.Token {
 			}
 			if name == 'VMOD_FILE' {
 				if s.vmod_file_content.len == 0 {
-					vmod_file_location := vmod.mod_file_cacher.get( os.dir( os.real_path(s.file_path) ) )
+					vmod_file_location := vmod.mod_file_cacher.get_by_file( s.file_path )
 					if vmod_file_location.vmod_file.len == 0 {
 						s.error('@VMOD_FILE can be used only in projects, that have v.mod file')
 					}

vlib/v/vmod/vmod.v

@@ -58,7 +58,13 @@ pub fn (mcache &ModFileCacher) dump() {
 	}
 }
 
-pub fn (mut mcache ModFileCacher) get(mfolder string) ModFileAndFolder {
+
+pub fn (mut mcache ModFileCacher) get_by_file(vfile string) ModFileAndFolder {
+	return mcache.get_by_folder( os.dir( vfile ) )
+}
+
+pub fn (mut mcache ModFileCacher) get_by_folder(vfolder string) ModFileAndFolder {
+	mfolder := os.real_path( vfolder )
 	if mfolder in mcache.cache {
 		return mcache.cache[ mfolder ]
 	}