test: preserve process.env after test-init exec

When LD_LIBRARY_PATH is overriden for custom builds we need to preserve
it for child processes. To be sure we preserve whole environment of
parent process and just add TEST_INIT variable to it.

test/simple/test-init.js

@@ -34,12 +34,16 @@
     // being in the test folder
     process.chdir(__dirname);
 
-    child.exec(process.execPath + ' test-init', {env: {'TEST_INIT': 1}},
+    // slow but simple
+    var envCopy = JSON.parse(JSON.stringify(process.env));
+    envCopy.TEST_INIT = 1;
+
+    child.exec(process.execPath + ' test-init', {env: envCopy},
         function(err, stdout, stderr) {
           assert.equal(stdout, 'Loaded successfully!',
                        '`node test-init` failed!');
         });
-    child.exec(process.execPath + ' test-init.js', {env: {'TEST_INIT': 1}},
+    child.exec(process.execPath + ' test-init.js', {env: envCopy},
         function(err, stdout, stderr) {
           assert.equal(stdout, 'Loaded successfully!',
                        '`node test-init.js` failed!');
@@ -48,7 +52,7 @@
     // test-init-index is in fixtures dir as requested by ry, so go there
     process.chdir(common.fixturesDir);
 
-    child.exec(process.execPath + ' test-init-index', {env: {'TEST_INIT': 1}},
+    child.exec(process.execPath + ' test-init-index', {env: envCopy},
         function(err, stdout, stderr) {
           assert.equal(stdout, 'Loaded successfully!',
                        '`node test-init-index failed!');
@@ -59,7 +63,7 @@
     // expected in node
     process.chdir(common.fixturesDir + '/test-init-native/');
 
-    child.exec(process.execPath + ' fs', {env: {'TEST_INIT': 1}},
+    child.exec(process.execPath + ' fs', {env: envCopy},
         function(err, stdout, stderr) {
           assert.equal(stdout, 'fs loaded successfully',
                        '`node fs` failed!');