fix(gatsby): test plugin name to handle symlinks, rather than path

This simple PR augments the behavior to test the plugin's name, rather
than the plugin's resolved path, in the case that it could be
symlinked/linked. This seems to match the behavior we're expecting, and
_again_ will be cleaned up when gatsbyjs#10787 lands.

packages/gatsby/src/internal-plugins/query-runner/__tests__/query-compiler.js

@@ -68,7 +68,12 @@ describe(`resolveThemes`, () => {
   it(`returns empty array if zero themes detected`, () => {
     ;[
       [],
-      [{ resolve: path.join(base, `gatsby-plugin-whatever`) }],
+      [
+        {
+          name: `gatsby-plugin-whatever`,
+          resolve: path.join(base, `gatsby-plugin-whatever`),
+        },
+      ],
       undefined,
     ].forEach(testRun => {
       expect(resolveThemes(testRun)).toEqual([])
@@ -80,6 +85,7 @@ describe(`resolveThemes`, () => {
     expect(
       resolveThemes([
         {
+          name: theme,
           resolve: path.join(base, `gatsby-theme-example`),
         },
       ])
@@ -92,6 +98,7 @@ describe(`resolveThemes`, () => {
     expect(
       resolveThemes([
         {
+          name: theme,
           resolve: path.join(base, theme),
         },
       ])

packages/gatsby/src/internal-plugins/query-runner/query-compiler.js

@@ -66,7 +66,7 @@ const overlayErrorID = `graphql-compiler`
 
 const resolveThemes = (plugins = []) =>
   plugins.reduce((merged, plugin) => {
-    if (plugin.resolve.includes(`gatsby-theme-`)) {
+    if (plugin.name.includes(`gatsby-theme-`)) {
       merged.push(plugin.resolve)
     }
     return merged