Removed instrument check before saving sourceMap. Updated the changelog with this pull

Author: Aftabnack

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### Fixes
 
+* `[jest-runtime]` Removed check for `mapCoverage` boolean before attempting to read inlineSourceMaps. [#5177](https://github.com/facebook/jest/pull/5177)
 * `[jest-cli]` Fix `EISDIR` when a directory is passed as an argument to `jest`.
   ([#5317](https://github.com/facebook/jest/pull/5317))
 

integration_tests/__tests__/__snapshots__/coverage_remapping_inline_sourcemap.test.js.snap renamed to integration-tests/__tests__/__snapshots__/coverage_remapping_inline_sourcemap.test.js.snap

@@ -243,6 +243,8 @@ export default class ScriptTransformer {
     }
 
     if (!transformed.map) {
+      //Could be a potential freeze here.
+      //See: https://github.com/facebook/jest/pull/5177#discussion_r158883570
       const inlineSourceMap = convertSourceMap.fromSource(transformed.code);
       if (inlineSourceMap) {
         transformed.map = inlineSourceMap.toJSON();
@@ -259,7 +261,7 @@ export default class ScriptTransformer {
       code = transformed.code;
     }
 
-    if (instrument && transformed.map) {
+    if (transformed.map) {
       const sourceMapContent =
         typeof transformed.map === 'string'
           ? transformed.map