Removed first partition, how to resize second partition into the free space?
I assume, to added Sierra, you shrunk the Mavericks volume and created the "Macintosh HD" volume for Sierra. Installing Sierra created the "Recovery HD" volume. When you deleted Maverick you created free space above the Sierra volume. You can not add this free space back to the Sierra volume. You can only add free space if the space is directly below an existing HFS, Core Storage or APFS volume.

If you want to confirm where the free space is, then here are a few ways:


The sudo gpt -r show /dev/disk0 command will show the logical sector blocks used by each partition. The command will also show the free space between each partition in logical sector block units. In the days of OS X, you could run this command on the boot drives. Starting with macOS, System Integrity Protection (SIP) has to be disabled to do this.
Use the diskutil info -plist disk0s# command to retrieve partition number # start and size byte values. You need to repeat the command for each partition on a drive. Next, you can compile a table similar to the output from the gpt -r show /dev/disk0 command. Basically, free space is any space not allocated to a partition, the Protected Master Boot Record (PMBR) and the GUID Partition Tables (GPT).
Write a BASH script that would automate way number 2.  A free script can be downloaded from this site. Assuming your downloads goto to the default Downloads folder, you can get the free space by entering the command shown below. Note: You do not need to enter sudo or disable SIP. 

~/Downloads/driveinfo-1.0.1/driveinfo -cbestin disk0




  Frankly, I do not know if driveinfo is compatible with Sierra. If driveinfo is not compatible you will just get an error message saying so.


To reclaim the space, you have a few options:


Backup the Sierra volume using Time Machine or some other method. Erase you internal drive, create a new volume spanning the entire drive, then reload everything.
Use the gpt and newfs_hfs to create and format a new volume above the existing Sierra volume. You could then clone the Sierra volume to this new volume. I could post the steps for this, but I would first need the output from gpt -r show /dev/disk0 or ~/Downloads/driveinfo-1.0.1/driveinfo -cbestin disk0.