Update prebuilts to go1.8 ab/3753832

Test: m -j blueprint_tools
Change-Id: I93a8c971d66bc892c6892796791c689eb3bd1836
diff --git a/doc/install-source.html b/doc/install-source.html
index 4bf0ba3..45c5bbb 100644
--- a/doc/install-source.html
+++ b/doc/install-source.html
@@ -147,6 +147,9 @@
 which contains the Go 1.4 source code plus accumulated fixes
 to keep the tools running on newer operating systems.
 (Go 1.4 was the last distribution in which the tool chain was written in C.)
+After unpacking the Go 1.4 source, <code>cd</code> to
+the <code>src</code> subdirectory and run <code>make.bash</code> (or,
+on Windows, <code>make.bat</code>).
 </p>
 
 <p>
@@ -218,7 +221,7 @@
 Change to the directory that will be its parent
 and make sure the <code>go</code> directory does not exist.
 Then clone the repository and check out the latest release tag
-(<code class="versionTag">go1.7.4</code>, for example):</p>
+(<code class="versionTag">go1.8</code>, for example):</p>
 
 <pre>
 $ git clone https://go.googlesource.com/go
@@ -406,7 +409,7 @@
 <a href="//groups.google.com/group/golang-announce">golang-announce</a>
 mailing list.
 Each announcement mentions the latest release tag, for instance,
-<code class="versionTag">go1.7.4</code>.
+<code class="versionTag">go1.8</code>.
 </p>
 
 <p>